WO2010096374A2

WO2010096374A2 - Method and apparatus for controlling an actuatable restraint device using a side pressure sensor

Info

Publication number: WO2010096374A2
Application number: PCT/US2010/024275
Authority: WO
Inventors: Chek-Peng Foo; Huahn-Fern Yeh; Suthep Thanapathomsinchai; Rosalin Irwan
Original assignee: Trw Automotive U.S. Llc
Priority date: 2009-02-20
Filing date: 2010-02-16
Publication date: 2010-08-26
Also published as: KR20110137317A; EP2398675A4; US20100213693A1; EP2398675A2; WO2010096374A3; CN102325671B; KR101391381B1; EP2398675B1; CN102325671A; US8406959B2

Abstract

An apparatus for controlling an actuatable occupant restraint device of a vehicle comprises a central crash accelerometer that senses crash acceleration at a vehicle location and that, provides a first crash acceleration signal indicative thereof. A side pressure sensor senses pressure in a chamber disposed at a side of the vehicle and provides a side pressure signal indicative thereof. A controller actuates the actuatable occupant restraint device in response to the first crash acceleration signal and the side pressure signal The controller determines a first moving average of acceleration value comprising a moving average of acceleration in a direction generally perpendicular to a longitudinal axis of the vehicle determined from the first crash acceleration signal. The controller determines a change in pressure value comprising a change in pressure In the chamber determined from the side pressure signal. The controller actuates the actuatable occupant restraint device when both the first moving average of acceleration value exceeds a first threshold and the change in pressure value exceeds a second threshold.

Description

- I-

METHOD AND APPARATUS FOR

CONTROLLING AN ACTUATABLE

RESTRAINT DEVICE USING A SIDE PRESSURE SENSOR

Related Application This application claims priority from U.S. Foo et ai. Patent Application

Serial No. 12/390,081. filed February 20_s 2009, the subject matter of which is incorporated hereby incorporated by reference in its entirety.

Field of the invention

The present invention relates to a method and apparatus for controlling a vehicle actuatable occupant restraint device and, particularly, for controlling a vehicle actuatable occupant restraint device using a side pressure sensor.

Background of the Invention

Actuatable occupant restraini systems are used to help protect occupants of a vehicle in the event of a vehicle crash. Such an actuatable occupant restraint system may include an inflatable occupant restraint device, such as an air bag, to help protect a vehicle occupant in the event of a side impact crash.

U.S. Patent Na 5,935,182 to Foo et al., assigned to TRW Inc., discloses a method and apparatus for discriminating a vehicle crash condition using virtual sensing. U.S. Patent No. 6,520,536 to Foo et al., also assigned to TRW Inc., discloses a method and apparatus for controlling an occupant side restraining device using vehicle side mounted accelerometers to provide an enhanced side safmg function. U.S. Patent No. 6,529,810 to Foo et al., also assigned to TRW Inc., discloses a method and apparatus for controlling an actuatable multistage restraint device using several thresholds based on transverse acceleration. U.S. Patent Application Publication No. 2006/0255575 to Foo et al,, assigned to TRW

Automotive U.S. U-C. discloses a method and apparatus for controlling an actuatable restraining device using XY side satellite accelerometers. Sαiamarv of the. Invention

The present invention is directed to a method and apparatus for controlling a vehicle actυatable occupant restraint device using a side pressure sensor. in a representative embodiment of the present invention, an apparatus for controlling an actuatable occupant restraint device of a vehicle comprises a crash accelerometer that senses crash acceleration at a vehicle location and that provides a first crash acceleration signal indicative thereof. A side pressure sensor senses pressure in a chamber disposed at a side of the vehicle and provides a side pressure signal indicative thereof. A controller actuates the actuatable occupant restraint device in response to the first crash acceleration signal and the side pressure signal.

The controller determines a first moving average of acceleration value comprising a mos ing average of acceleration in a direction general!) perpendicular to a longitudinal axis of the vehicle determined from the first crash acceleration signal. The controller determines a change in pressure value comprising a change in pressure in the chamber determined from the side pressure signal. The controller actuates the actuatable occupant restraint device when both the first moving average of acceleration value exceeds a first threshold and the change in pressure value exceeds α second threshold

In accordance with another embodiment of the invention, a method is provided for controlling actuation of an actuatable occupant restraint

ice of a vehicle. The method comprises the step of sensing crash acceleration at a vehicle location and providing a first acceleration signal Indicative thereof. The method also comprises the step of sensing pressure in a chamber disposed at a side of the vehicle and pro\ iding a side pressure signal mdicath e thereof. The method further comprises the step of determining a first moving average of acceleration value comprising a moving average of acceleration in a direction generaϊlv perpendicular to a longitudinal axis of the -vehicle determined from the first crash acceleration signal. The method still further comprises the t,teρ of determining a change in pressure value comprising a change in pressure in the chamber determined from the side pressure signal. The method yet further comprises the step of actuating the actuatable occupant restraint device when both the tint moving average of acceleration value exceeds a first threshold and the change in pressure value exceeds a second threshold.

Brief Desenpf ion of the Drawings

The foregoing and other features and advantages of the invention will become apparent to one skilled in the art upon consideration of the following description of the invention and the accompanying drawings, in which:

Fig. 1 is a schematic diagram of a vehicle having an actuatahle occupant restraint system that is controlled by an apparatus in accordance with an example embodiment of the present invention; Fig. 2 is a sectional view of a driver side vehicle door with a side pressure sensor of the apparatus of Fig. 1 :

Fig. 3 is a sectional view of a passenger side vehicle door with a side pressure sensor of the apparatus of Fig. 1 :

Fig. 4 is an electrical schematic block diagram of the apparatus of Fig. 1 ; Fig. 5 is a logic diagram showing an example embodiment of the control logic used by an apparatus in accordance with the present invention;

Fig. 6 is a logic diagram showing a second example embodiment of the contra! logic used by an apparatus in accordance with the present invention; and

Fig. 7 is a logic diagram showing a third example embodiment of the control logic used by an apparatus in accordance with the present invention.

Pet ailed Description

As shown in Figs, i through 4, an apparatus 10 is mounted in a vehicle 12 for controlling the actuation of an actuatable occupant restraint system 14, in accordance with an example of (he present invention. The actuatable occupant restraint system 14 comprises a first side impact inflatable occupant restraint device 16, such as a door-mounted air bag module (shown in Fig. 2). a seat- mounted air bag module, or a roof rail-mounted curtain air bag module, located on a driver side 18 of the vehicle 12. The first side impact inflatable occupant restraint device 16 is preferably located in or adjacent to side structure of the vehicle 12. which includes vehicle doors, pillars, and side body panels. The actustabie occupant restraint system 14 also comprises a second side impact inflatable occupant restraint device 20, such as a door-rnoiMed air bag module (shown in Fig. 3), a seat-mounted air bag module, or a roof rail-mounted curtain air bag module, located in or adjacent to side structure on a passenger side 22 of the vehicle 12. The actuatable occupant restraint system 14 may further or alternatively comprise a seat belt occupant restraint device, such as a driver side seat belt pretensioner 24 and/or a passenger side seat belt pretensioπer 26. The actuatable occupant restraint system 14 may still further or alternatively comprise any actuatable occupant restraint device that helps to protect a vehicle occupant in response to a side impact to the vehicle 12.

The apparatus 10 comprises a crash or collision sensor assembly 30 located at a generally central location in the vehicle. The sensor assembly 30 includes a first crash acceleration sensor 32, which is preferably an accelerorøeter, having its axis of sensitivity oriented to sense crash acceleration in a direction generally parallel to a transverse or side-to-side axis of the vehicle 12. The transverse axis is designated the Y axis in fig. 1 and is oriented perpendicular to the longitudinal or front-to-rear axis of the vehicle 12, which is designated the X axis in Fig. 1. The first crash acceleration sensor 32 provides a crash acceleration signal designated CCLM Y. The sensor assembly 30 may also comprise a second crash acceleration sensor 34, which is preferably an accelerometer. having its axis of sensitivity oriented to sense crash acceleration in a direction generally parallel to the X axis. The second crash acceleration sensor 34 provides a crash acceleration signal designated CCUJ X. The sensor assembly 30 may further comprise a ihird crash acceleration sensor 36, which is preferably an accelerometer, having its axis of sensitivity oriented to sense crash acceleration in a direction generally parallel to the X axis. The third crash acceleration sensor 36 provides a crash acceleration signal designated CCU_2X.

The first crash acceleration sensor 32 preferably has a nominal sensitivity of ± 20g^"s (g being the value of acceleration due to earth's gravity, i.e., 32 feet per second squared or 9.8 meters per second squared). The second and third crash acceleration sensors 34 and 36 preferably have nominal sensitivities of ± lOOg's and ± SOg^'s, respectively.

The crash acceleration signals CClLlY, CClMX, and CCϋ_2X from the crash acceleration sensors 32, 34, and 36, respectively, can take any of several forms. Each of the crash acceleration signals CCU_1Y. CCUJX, and CCU_2X can have amplitude, frequency, pulse duration, or any other electrical characteristic that varies as a function of the sensed crash acceleration. In the embodiment of Figs. 1-4, the crash acceleration signals CCU-IY, CCTMX, and CCU_2X have frequency and amplitude characteristics indicative of the sensed crash acceleration. Thus, each of the crash acceleration signals CCUJY, CCU _..JX₅ and CCU_2X is functionally related to the sensed crash acceleration along the axis of sensitivity of the corresponding crash acceleration sensor 32, 34 or 36, respectively.

The apparatus 10 also comprises a driver side satellite crash acceleration sensor 40, which is preferably an accelerometer, located in or adjacent to side structure on the driver side 18 of the vehicle 12, such as in the driver side vehicle

B-piliar 42 or in the driver side door 44. The side satellite crash acceleration sensor 40 has an axis of sensitivity oriented to sense crash acceleration in a direction generally parallel to the vehicle's Y axis and provides a signal designated RASJBY. The apparatus 10 further comprises a passenger side satellite crash acceleration sensor 46, which is preferably an accelerometer, located in or adjacent to side structure on the passenger side 22 of the vehicle 12» such as in the passenger side B-piilar 48 or m the passenger side door 50, The side satellite crash acceleration sensor 46 has an axis of sensitivity oriented to sense crash acceleration in a direction generally parallel to the vehicle's Y axis and provides a signal designated as RAS_2BY.

The crash acceleration signals RASJBY and RAS_2BY from the side satellite crash acceleration sensors 40 and 46. respectively, can take any of several forms, Each of the crash acceleration signals RAS I SY and RAS 2BY can have amplitude, frequency, pulse duration, or any other electrical characteristic that varies as a function of the sensed crash acceleration. Ia the embodiment of

Figs. 1-4, the crash acceleration signals RAS IBY and RAS 2BY have frequency and amplitude characteristics indicative of the sensed crash acceleration in a direction generally parallel to the

Y axis Thus, each of the crash acceleration signals RASJ BY and RAS 2BY is functional!) related to the sensed crash acceleration along the axis of sensitivity of the corresponding side satellite crash acceleration sensor 40 or 46, respectively.

Other Y axis side satellite crash acceleration sensors may be included in the apparatus 10. ^uch Y-axis side satellite crash acceleration sensors may be mounted in or adjacent to C-pi liars 43 and 45 on the driver side 1 S and passenger side 22, respeetή ely, of the vehicle 12 snό 'ot in or adjacent to D-piilars 47 and 49 on the driver side 18 and passenger side 22, respectively, of the

If C-pillar and 'or D-piliar side satellite crash acceleration sensors axe used, the> provide .signals designated as RAS_C3Y (driver side C-pillar 43), RAS_C4Y (passenger side C-pillar 45), RAS. D5Y (drh εr side D-pillar 47), and RAS_D6Y (passenger side D-pillar 49), ϊn the embodiment of the invention shown in Figs. 1-4, however. onl) side satellite crash acceleration sensors 40 and 46 are present,

Λ driver side pressure sensor 52 (Fig. 2 ), which is included in the apparatus 10. is located in the driver side door 44 of the vehicle 12. The driver side pressure sensor 52 iss mounted in a chamber 54 defined between the outer metal skin 56 of the driver side door 44 and the inner panel 58 of the door. The driver side pressure sensor 52 senses the pressure in the chamber 54 and provides a signal designated PSat I D. A similar passenger side pressure sensor 60 (Fig. 3), which is also included in the apparatus 10, is located in the passenger side door 50 of the vehicle 12. The passenger side pressure senior 60 is mounted in a chamber 62 defined between the outer metal skin 64 of the passenger side door 50 arsd the inner pane! 66 of the door. The passenger side pressure sensor 60 senses the pressure in the chamber 62 and provides a signal designed PSat 2 D.

The dm er side pressure sensor 52 and the passenger side pressure sensor 60 may be any t\ pe of pressure sensor suitable for sensing pressures in the chambers 54 and 62, respectively, and pro¹*, Ming signals indicathe of such pressures. The

side pressure sensor 52 and the passenger side pressure censor 60 røay be mounted at any location in or on the doors 44 and 50, respectively, that is suitable for sensing pressures in the chambers 54 and 62. Altemaϋvely, if the side structure of the vehicle 12 defines one or more other chambers in which the pressure may be affected by a vehicle crash, the driver and passenger side pressure sensors 52 aid 60 may be mounted to sense the pressure in one or more of such other chambers. The apparatus 10 may optionally include a satellite sating acceleration sensor 68, which is preferably an accelerometer, having its axis of sensitivity oriented to sense crash acceleration in a direction generally parallel to the Y axis. The satellite safmg acceleration sensor 68 is preferably located in a plane that passes through the X axis of the vehicle 12 but is offset rearward of the collision sensor assembly 30, The satellite sating acceleration sensor 68 provides a crash acceleration signal designated SSSJ Y and preferably has a nominal sensitivity of ± 250g^!s. The crash acceleration signal SSSJ Y can take any of several forms. The crash acceleration signal SSSJY can have amplitude, frequency, pulse duration, or any other electrical characteristic that varies as a function of ihe sensed crash acceleration. In the embodiment of Figs, 1-4, the crash acceleration signal SSSJ Y has frequency and amplitude characteristics indicative of the sensed crash acceleration. Thus, the crash acceleration signal SSSJY is functionally related to the sensed crash acceleration along the Y axis of sensitivitj , The crash acceleration signals CCUJ Y, RASJ BY, and RASJ2BY from the crash acceleration sensors 32, 40 and 46. respectively, the crash acceleration signal SSSJY from the satellite safmg acceleration censor 68, and the side pressure signals PSatJD and PSai_2D from the driver and passenger side pressure sensors 52 and 60, respectively are provided to a controller 70 (Fig. 4). The controller 70, which is included in the apparatus 10, is preferably a microcomputer programmed to execute a control process, including one or more algorithms, in accordance with the present invention. The functions performed by the controller 70 could, however, be carried out by other digital and/or analog circuitry, including separate electrical or electronic components, which could be assembled on one or more circuit boards or as an application specific integrated circuit CASK?^*}- -S-

The controller 70 monitors lhe crash acceleration signals CCU_1Y, RASJBY. and RAS_2BY from the crash acceleration sensors 32. 40 and 46, respectively, and the side pressure signals PSatJD and PSat 2D from the driver and passenger side pressure sensors 52 and 60, respectively. The controller 70 executes one or more algorithms, as described in greater detail below, to determine whether a crash event is occurring for which actuation or deployment of the actuatable occupant restraint system 14 is desired and to discriminate between such a deployment crash event and a non-deploymeπl crash event for which actuation or deployment of the actuatable occupant restraint system 14 is not desired. The algorithms determine values from the crash acceleration signals CCUJ Y,

RASJBY, and RASJSY and the side pressure signals PSatJD and PSatJD. The determined values are used in deployment or actuation decisions. If a decision is made in accordance with the determined values to deploy or actuate the actuatable occupant restraint system 14 or a portion of the system, such as the first side impact inflatable occupant restraint device 16 or the second side impact inflatable occupant restraint device 20. the controller 70 outputs an appropriate deployment signal or command.

The apparatus 10 preferably uses only the crash acceleration signals CCl-LlY, RASJ BY, and RASJ2BY and the side pressure signals PSmJU and PSat _2D in deployment or actuation decisions. The apparatus 10 may alternatively also employ one or more of the crash acceleration signals SSSJY, CCU 1 X, and CCU 2X, with or without filtering, in deployment or actuation decisions. Other signals that may be received and employed in deployment or actuation decisions, in addition to the crash acceleration signals CCU IY, RAS J BY, and RASJBY and the side pressure signals PSatJD and PSat_2D. are signals RAS C3Y. RAS...C4Y. RAS_D5Y, and RASJW from optional C-psIlar and/or 0-rjiilar side satellite crash acceleration sensors. Still other signals that may- be received and employed in deployment or actuation decisions may include signals from a driver and/or passenger seat belt buckle switch sensor that provides a signal indicating whether the buckle is latched or unlatched, a driver and/or passenger weight sensor that provides a signal indicative of the seat occupant's sensed weight, and sensors that provide signals indicative of other vehicle occupant information, such as presence, position, height, girth, movement and/or use of a child seat

The controller 70 controls the actuatable occupant restraint system 14 in accordance with a control process and iogic. One embodiment of the control process and logic is shown in Fig. 5. Hie process and logic of Fig, 5 is specifically directed to controlling an actuatable occupant restraint device on the driver side 18 of the vehicle 12, such as the first side impact inflatable occupant restraint device 16. Fig. 5 is nonetheless representative of a process and logic that may be used to control the second side impact inflatable occupant restraint device 20 on the passenger side 22 of the vehicle 12 and any other actuatable occupant restraint device that helps to protect a vehicle occupant in response to a side impact to the vehicle 12. in the control process of Fig. 5, the crash acceleration sensor 32 provides an acceleration signal CCLMY having a characteristic (e.g., frequency and amplitude) indicative of the vehicle's crash acceleration in a direction generally parallel to the V axis of the vehicle 12 upon the occurrence of a crash event. The acceleration signal CCU_1 Y is provided to two low-pass-filter ("LPF") functions 76 and 78 of the controller 70. The LPF functions 76 and 78 operate in parallel and filter the acceleration signal CClMY to eliminate extraneous signal components, such as. frequencies resulting from extraneous vehicle operating events and/or from road noise. The signal components removed through filtering are not useful in discriminating a vehicle crash event for which deployment of a driver side actuatable occupant restraint device, such as the first side impact inflatable occupant restraint device 16. is desired. Empirical testing is used to determine the signal components useful for crash discrimination in a vehicle of interest. For reasons that will be explained below, the LPF functions 76 and 78 typically filter different signal components from the acceleration signal CClMY. Signal components indicative of a crash event are passed for further processing. The filtered output signal from the LPF function 76 is provided to an analog-to-digital (''AZO") converter function 80 of the controller 70, The A/D converter function 80 converts the filtered crash acceleration signal into a digital signal. The output of the A/D converter function 80 may be filtered with another fύtcv function (not shown) having filter values empirical!}' determined for the purpose ot eliminating small drifts and offsets associated with the AfD conversion. This other filter function would be digitally implemented within the controller 70. A determination function 84 of the controller 70 determines a crash metric value j| A | _MA_A_S_CCU_ IY from the filtered crash acceleration signal CCUJ Y,

In parallel, the filtered output signal from the LPF function 78 is provided to an AfD converter function 82 of the controller 70. The AID converter function 82 converts the filtered crash acceleration signal into a digital signal. The output of the A/D converter function 82 mav be filtered with another filter function

(not shown) having filter values empirical!}' determined for the purpose of eliminating small drifts and offsets associated with the A/D conversion. This other filter function would be digitally implemented within the controller 70. A determination function 86 of the controller 70 determines a crash metric value | A | JdA_A JSS JXU I Y from the filtered crash acceleration signal CCU J Y.

The values | A ||J4A_A_S CCUJY and ||A | _MA_AJ3S_CCUJ Y are moving averages of the absolute values of acceleration as sensed by the first crash acceleration sensor 32. These values are determined by calculating moving averages of the absolute values of the associated filtered acceleration signal CCUJ Y from the first crash acceleration sensor 32. A moving average is the sura of the last predetermined number of samples of the filtered acceleration signal divided by the number of samples. The average is updated b> removing the oldest sample, replacing it with the latest sample, and then determining the new average. As the average value changes or "moves" over time, it is referred to as a

''moving average^1'. The value jj A jj MA_A_SSJXU J Y is determined using a smaller number of samples than the number of. samples used to determine the value [J A |_MA_A_SJX.^'U IY. Empirical testing is used to determine the number of samples to be used for each of the values jj A | MA A JS JXU J Y and [j A jj_MA_AJSS JXU J Y. The difference in the number of samples m&ά to determine the values | A f _MA_A JSJX¹UJ Y and g A || _MA_A_SS JX13JY affects which signal components are filtered by the LPF functions 76 and 78. The acceleration values | A ||_MA_A_SJXUJ Y and [J A J M A_A SSJXUJY are preferably determined using a virtual crash sensing process MIy described in U.S. Pat. No. 6,186,539 to Foo et al and U.S. Pat, No, 6,036,225 to Foo et ai. using a spring mass model of the occupant to account for spring forces and damping forces. A detailed explanation of a spring- mass model is found in U.S. Pat. No, 5,935,182 to Foo et al.

Comparison functions of the controller 70 compare the values | A || _MA_A_S_CCU _ I Y and jj A | _MA__A JSS JXU J Y against respective thresholds, which are preferably fixed but may be variable. Specifically, a comparison function 88 compares the | A [j JVf A _A S CXU J Y value against a first threshold 90, A comparison function 92 compares the [J A I JVΪA_A_SS JXUJ Y value against a second threshold 94. Empirical testing is used to determine values of the first and second thresholds 90 and 94 for a vehicle of interest. The occurrence of the jj A | _„ MA_AJS JXU J Y value exceeding the first threshold 90, as determined by comparison function 88, is latched by latch fimctton 96 of controller 70, which provides a digital HIGH signal to an AND function 10⁽3 of the controller. The occurrence of the j| A | MA_A_SS_€CU IY value exceeding the second threshold 94, as determined by comparison function 92, is latched by latch function 98 of controller 70, which provides a digital HIGH signal to the AND function 100. When the AND function 100 is ON or HIGH, as a result of receiving digital HIGH signals from both of the latch functions 96 and 98.. this occurrence is latched by a latch function 1 (32 of the controller 70. which provides a digital MGB signal to an ANO function 104 of the controller.

The driver side satellite crash acceleration sensor 40 provides an acceleration signal RASJBY having a characteristic (e.g., frequency and amplitude) indicative of the vehicle's crash acceleration in a direction generally parallel to the Y^' axis of Ae vehicle 12 upon fee occurrence of a crash event. The acceleration signal RASJ BY is provided to two LPF functions 106 and 108 of the controller 70. The LPF functions 106 and 108 operate in parallel and filter the acceleration signal RASJBY to eliminate extraneous signal components, such as, frequencies resulting from extraneous vehicle operating events and/or from road noise. The signal components removed through filtering are not useftii in discriminating a vehicle crash event for which deployment of a driver side actuatable occupant restraint device, such as the first side impact inflatable occupant restraint device 16. is desired. Empirical testing is used to determine the signal components useful for crash discrimination in a vehicle of interest. For reasons that will he explained below, the LPF functions 106 and 108 typically filter different signal components from the acceleration signal RAS__1SY. Signal components indicative of a crash event are passed for further processing. The filtered output signs! from the LPF function 106 is provided to an A/D converter function 1 10 of the controller 70. The A/D converter function 110 converts the filtered crash acceleration signal RAS_1BY into a digital signal. The output of the A/D converter function 1 10 may be filtered with another filter function (not shown) having filter values empirically determined for the purpose of eliminating small drifts and offsets associated with the A/D conversion. This other filter function would be digitally implemented within the controller 70. A determination function 1 14 of the controller 70 determines a crash metric value A__MA_A_S_RAS J BY from the filtered crash acceleration signal RAS JBY. In parallel, the filtered output signal from the LPF function 108 is provided to an A/D converter function 1 12 of the controller 70. The A/D converter function 1 12 converts the filtered crash acceleration signal into a digital signal. The output of the A/D converter function 1 Ϊ2 may be filtered with another filter function (not shown) having filter values empirically determined for the purpose of eliminating small drifts and offsets associated with the A'TJ conversion. This other filter function would be digitally implemented within the microcomputer. A determination function 116 of the controller 70 determines a crash metric value A_MA_A_SS_RAS_1BY from the filtered crash acceleration signai RASJBY. The values A >1A _^A JS JtAS JBY and A_MA_A_SS_RASJ BY are moving averages of acceleration as sensed by the driver side satellite crash acceleration sensor 40. These values are determined by calculating movinε average values of the associated filtered acceleration signal RAS 1 BY from the driver side satellite crash acceleration sensor 40. A moving average is the sum of the last predetermined number of samples of the filtered acceleration signal divided by έhe number of samples. The average is updated by removing the oldest sample, replacing it with the latest sample, and then determining the new average. As the average value changes or '*moves" over time, it is referred to as a "moving average^"'. The value A_MA_A_SS_RAS_1BY is determined using a smaller number of samples than the number of samples used to determine the value A_MA_A_S_RAS_1BY. Empirical testing is used to determine the number of samples to be used for each of the values A_MA_A_S_RAS_IBY and AJVΪA_A_SS_RAS_IBY. The difference in the number of samples used to determine the values A_MA_A_^S_mRAS_lBY and A_MA_AJSSJϊAS. J B affects which signal components are filtered by the LPF functions 106 and 108. Comparison functions of the controller 70 compare the values A_MA_A_S_RAS.J BY and A_MA_A_SSJRASJ BY against respective thresholds, which are preferably fixed but may be variable. Specifically, a comparison function 1 18 compares the A MA A SjRAS lBY value against a third threshold 120. A comparison function 122 compares the A_MA_A_SS_RAS_ IBY value against a fourth threshold 124, Empirical testing is used to determine values of the third aαd fourth thresholds 120 and 124 for a vehicle of interest.

The occurrence of the AJV1A_A S RAS_IBY value exceeding the third threshold 120, as determined by comparison function 1 18, is latched by latch function 126 of controller 70, which provides a digital HIGH signal to an AND function .130 of the controller. The occurrence of the A JVtA A ...SS RAS_J B Y value exceeding the fourth threshold 124, as determined by comparison function 122, is latched by a latch function 128 of controller 70, which provides a digital HIGH signal to the AND function 130. When the AND function 130 is ON or HIGH, as a result of receiving digital HIGH signals from both of the latch functions 126 and 128. this occurrence is latched by a latch function 132 of the controller 70. which provides a digital HIGH signal to the AND function 104 of the controller. When the AND function 104 is ON or H IGH₅ as a result of receiving digital HIGH signals from both of the latch functions 102 and 132, this occurrence is latched by a latch function 134 of the controller 70. which provides a digital HIGH signal to an AND function S 36 of die controller.

The driver side pressure sensor 52 provides the pressure signal PSaMD. which is indicative of the pressure in the chamber 54 in the driver side door 44 upon the occurrence of a crash event. The pressure signai PSaM D is provided to an A/D converter function OS of the controller 70. The A/D converter function 138 converts the pressure signal PSaMD into a digital signai. The output of the A/D converter function 138 is provided to a determination function 140 of the controller 70, which determines a crash metric value ΔP/Pr,_? where ΔP is the change in pressure as determined by two pressure values measured at different times &nd Po is ambient pressure outside the vehicle 12.

A comparison function 142 of the controller 70 compares the value ΔP/Po against a fifth threshold 144. which is preferably fixed but may be variable. The occurrence of the ΔP/Po value exceeding the fifth threshold 144, as determined by comparison function 142, is latched by a latch function 146 of controller 7(3, which provides a digital IiIGH signal to the AND function 136 of the controller. When the AND function 136 receives digital HIGH signals from both the latch function 146 and the latch function 134, the AND function 136 is ON or HIGH, Irs response to the AND function 136 being ON or HIGH, a deployment control function 148 of the controller 70 outputs a deployment signal to a driver side actuatabie occupant restraint device, such as the first side impact inflatable occupant restraint device 16, which deploys in response to the deployment signal. A second embodiment of the control process and logic used by the controller 70 to control the actuatabie occupant restraint system 14 is shown in

Fig, 6. The process and logic of Fig. 6 is specifically directed to controlling an actuatabie occupant restraint device on the driver side 18 of the vehicle 12, such as the first side impact inflatable occupant restraint device 16. Fig, 6 is nonetheless representative of a process and logic that may be used to control the second side impact inflatable occupant restraint device 20 on the passenger side 22 of the vehicle 12 and any other actuatabie occupant restraint device that helps to protect a vehicle occupant in response to a side impact to the vehicle 12. In the control process of Fig, 6, the first crash acceleration sensor 32 provides an acceleration signal CCU 1 Y to the controller 70» and the controller processes the signal CClMY hi the same manner and with the same functions as in the control process of Fig. 5 through and including the AND function 104 of the controller. The control process of Fig. 6 differs, however, from έhe control process of Fig. 5 with respect to the processing of the acceleration signal RAS_1 BY from the driver side satellite crash acceleration sensor 40 and the pressure signal PSa! LD from the drh'cr side pressure sensor 52, as explained below ,

The driver side pressure sensor 52 provides the pressure signal PSat_lD, which is indicative of the pressure in the chamber 54 in the driver side door 44 upon the occurrence of a crash event, to an AO con\ erter function 150 of the controller 70. The A'D converter function 150 converts the pressure signal PSat_l D into a digital signal. The output of the A/D converter function 150 Is provided to a determination function 152 of the controller 70, which determines a crash metric value

where ΛP is the change in pressure as determined b> two pressure values measured at different times and Po is ambient pressure outside the \ chicle 12.

A comparison function Ϊ 54 of the controller 70 compares the \alue ΔP'P_υ against a sixth threshold 156. which is preferably fixed but may be variable. The occurrence of the APZP₀ value exceeding the sixth threshold 15(>. as determined by comparison function 154, is latched by a latch function 158 of controller 70, which prov ides a digital HiGIl signal to the AND function 104 of the controller. When the AND function 104 is ON or HIGH, as a result of receiving digital HIGH signals from both of the latch functions 102 and 158, this occurrence is latched by a latch function 160 of the controller 70, v> hich pan ides a digital HIGH signal to

AND function 178 of the controller.

The driver side satellite crash acceleration sensor 40 ρro\ ides the acceleration signal RAS_1BY, which is indicativ e of the vehicle^'s crash acceleration in a djrection generally parallel to the Y axis of the vehicle ! 2 upon the occurrence of a crash event, to an LPF function 162 of the controller 70. fhe

LPF function 162 filters the acceleration signal RAS I BY to eliminate exttaneoυs signal components, such as. frequencies resulting from extraneous vehicle operating e\ ents and' or fiom road noise. The signal components rcrøcΛ ed through filtering are not useful in discriminating a vehicle crash event for which deployment of a driver side actuatable occupant restraint device, such as the first side impact inflatable uccupant restraint device J 6, is desired. Fmpirical testing is used to determine the signal components useful for crash discrimination in a vehicle of interest. Signal components indicative of a crash event are passed for further processing

The filtered output signal from the LPF function 162 is provided to an A D converter function 164 of the controller 70. The A- D converter function 164 converts the filtered crash acceleration signal RΛS_^IBY into a digital Signal. The output of the AvO tυnvettei function 164 ma> be filtered with another filter function (not shown) hav ing filter values empirically determined for the purpose of eliminating small drifts and offsets associated w ith the .-Vf) conversion This other filter function would be digital!} implemented within the controller 70, A determination function 166 of the controller 70 determines a crash metric

\alue A_MΛ RAS_1BY from the filtered crash acceleration signal RAS IBY.

In parallel, the crash acceleration signal CCU_ IY from the first crash acceleration sensor 32 is provided to an 1 PF function 168 of the controller 70. Fhe LPF function 168 filters the acceleration signal C¹CLMY to eliminate cxtianeous signal components, such as, frequencies resulting from extraneous \ ehicle operating events anώor from road noise. The signal components removed through filtering are not useful in discriminating a vehicle crash event foi which deploy røent of a driver side actuatable occupant restraint dev ice. such as the first side impact inflatable occupant restraint device 16, is desired. Fmpiπeal testing is. used to determine the signal components useful for crash discrimination in a vehicle of interest. Signal components indicative of a cra^h event are passed for further processing.

The filtered output signal from the LPF function 168 is provided to an Λ 'D convener function 170 of the controller 70. The A/D converter function 170 converts the filtered cra^h acceleration pigna! into a digital signal. The output of the A/D converter function 170 ma> be filtered v\ ith another filter function (not shown) having filter values empirical!} determined for the purpose of eliminating sniali ώ ifts and offsets associated with the AB com ersϊon. I hi? other fitter function would be digϊtaiK implemented within the microcomputer. The digital filtered output sigtul from ihe AD converter function 170 is provided to the determination function 166 of the controller 70. which determines a crash metric value \_MΛ_C'Cl M Y from the filtered crash acceleration signal CCUJY.

Tac

BY are moving averages of acceleration as sensed by the first crash acceleiation sensor 32 sπd the driver 5'de satellite crash acceleration sεnsoi 40. rcspectn ely These values are determined b> calculating moving a\ α age values of the associated filtered acceptation signals CCU_1 Y and RAS__1 BY from the first crash acceleration sensor 32 and the drive! side satellite crash accelcialion sensor 40. Λ moving average, as pieviousfy explained, is the sum of the Ust predetermined nunϊber of samples of ihe filtered acceleration signal divided by the number of samples. 1 he av erage Is updated bj removing the oldest sample, replacing it with the latest sample, and then determining the new average. <Vs the average value changes or

"moves" over time, it is referred to as a "moving average", HiTipiπcal testing is used to determine the number of samples to be used for each of the values A MAJX IMY aπci \>1<\_RAS !BY

A comparison function U2 of the controller 70 compares the Λ due A_MA_RAS 1 BY against a threshold, which is preferably variable but may be fixed. Specifically, the comparison function 172 compares the A_MA_RAS_1 BY value ab a function of the A_MΛ_CCU_1\ value against a

174. A graphical representation of the variation of the seventh threshold 174 is included in Fig, ft. As can be seen, with increasing valuer of A M _'\_RΛS_ 1 BY. the se\ enth threshold 174 general!} increases as the

increases Rmpiπcal testing is used to determine the v ariation in the seventh threshold 174 as a function of the mouug average value A MΛ CCU I Y, The occurrence of the AJVL4_RAS_IBY v alue exceeding the seventh threshold 174, as determined by comparison {unction 172. is latched b> a iatch function 176 of the controlki 70, which prov ides a digital HIGH signal to the 4>iD function 178 of the controller When the AND function 178 recenes digital HIGH signals from both the latch function 176 and the latch function 158, the 4.NΪ) function 178 is ON or HIGH. In response to the AND function ! 78 being ON or HIGIL a deployment control function 179 of the controller 70 outputs a deployment signal to a driver side acatatable occupant restraint device, such as the first side: impact inflatable occupant restraint de\ ice 16. which deploys in response to the dep!o>rtient signal

Λ third embodiment of the control process and logic used by the controller 70 to control the actuatable occupant restraint s> stern 14 is shown in Fig. 7. The process and logic of Fig, 7 is specificalh directed to controlling an actuatable occupant restraint device on the driver side 18 of the vehicle 12, such as the first side impact inflatable occupant restraint device 16. Fig, 7 i_. nonetheless

of a process and logic that may be used to control the second side impact inflatable occupant iestraint

20 on the passenger side 22 of the vehicle 12 and an> other actuatable occupant restraint device that helps to protect a vehicle occupant in response to a side impact to the vehicle 12.

In the control process of Fig. 7. the first crash acceleration censor 32 provides the acceleration signal CCUJY to the controller 70. the driver side satellite cr&sh acceleration sensor 40 provides the acceleration signal RASJBY to the controller, and the driver side pressure sensor 52 provides the pressure signal PSat_lD to the controller, as is done in the control process uf Fig. 5 The controller 70 processes the signals CCLJY, RASJ BY, and PSat ID in substantial!} the same manner and with substantial!} the Name functions as in the control process of Fig. 5 The control process of Hg. 7 differs, however, from the control process of Hg. 5 in that the control process of Hg. 7 also monitors and processes the crash acceleration signal SSS 1 Y from the satellite safmg acceleration sensor 68 1 his processing of the crash acceleration signal SSSJY. w hkh occurs hi parallel with the processing of the crash acceleration signal CCU 1 Y, is explained below

In the control process of Fig. 7. the satellite sating acceleration sensor 68 provides the acceleration signal SSS i Y. which is indicative of the vehicle's crash acceleration in a direction generall) parallel tt_< the Y axis of the vehicle 12 upon the occurrence of a crash event, to t\\ o LPF functions 180 and 1 82 of the controller 70. The LPF Functions 180 and 182 operate in parallel and filter the acceleration signal SSS JY to eliminate extraneous signal components, such as, frequencies resulting from extraneous vehicle operating events and/or from road noise. The signal components removed through filtering are not useful in discriminating a vehicle crash event for which deployment of a driver side actisatable occupant restraint device, such as the first side impact inflatable occupant restraint device 16, is desired. Empirical testing Is used to determine the signal components useful for crash discrimination in a vehicle of interest. For reasons that will be explained below, the LPF functions 180 aid 182 typically filter different signal components from the acceleration signal SSS_ 1 Y. Signal components Indicative of a crash event are passed for further processing.

The filtered output signal from the LPF function ! 80 is provided to an A/D converter function 184 of the controller 70. The A/D converter function 184 converts the filtered crash acceleration signal into a digital signal. The output of the A/D converter function 184 may be filtered with another filter function (not shown) having filter values empirically determined for the purpose of eliminating smalt drifts and offsets associated with the A/D conversion. This other filter function would be digitally implemented within the controller 70. A determination function 588 of the controller 70 determines a crash metric value | A |_MA_A S SSSJY from the filtered crash acceleration signal SSSJY. ϊn parallel, the filtered output signal from the LPF function 182 is provided to an A/D converter function Ϊ 86 of the controller 70, The A/D converter function 186 converts the filtered crash acceleration signal into a digital signal The output of the A/D converter function 186 may be filtered with another filter function (not shown) having litter values empirically determined for the purpose of eliminating small drifts and offsets associated with the A/D conversion. This other filter function would be digitally implemented within the controller 70. A determination function 190 of the controller 70 determines a crash metric value jj A jj _MA_A .SS ...SSSJ Y from the filtered crash acceleration signal SSSJY. The values jj A |_MA_A_S_SSSJY and | A |_MA. A. SSJSSSJ Y are moving averages of the absolute values of acceleration as sensed b> the satellite safmg acceleration sensor 68. These values are determined by calculating moving averages of the absolute

of the associated filtered acceleration signal SSS J Y from the satellite safmg acceleration sensor 68. A moving average, as previously explained, is the sum of the last predetermined number of samples of fee filtered acceleration signal divided by the number of samples. The average is, updated by removing the oldest sample, replacing it with the latest sample, and then determining the new average. As the average value changes or ""moves" over time, it is referred to as a "moving average^". The value I A j| JVIA_A_SS_SSS 1 Y is determined using a smaller number of samples than the number of samples used to determine the value jj A [j_MA_A_S_SSSJ Y. Empirical testing is used to determine the number of samples to be used for each of the values || A | ..MA _A_S_S$S J Y and |j AJj >IA_A_SS_$SSJY. The difference in the number of samples used to determine the values || A | _MA A_S_S>SS_IY and || A ||_MA_A_SS_SSS J Y affects which signal components are filtered by the LPF functions 180 and 182.

Comparison functions of the controller 70 compare the values J A || _MA_ A .SJiSSJ Y and jj A || . MA_A_SS_SSS_ 1 Y against respective thresholds, w hich are preferably fixed but may be \ ariable.

Specifically, a comparison function 192 compares the | A || _MA_A ...S SSSJY value against an eighth threshold 194, A comparison function 196 compares ^tϊie I A I _MA_A_SS_SSS__1 Y \ alue against a ninth threshold 198, Empirical testing is used to determine values of the eighth and ninth thresholds i 94 and 198 for a vehicle of interest,

I he occurrence of the | A | JViA ..A. S SSS_1 Y value exceeding the eighth threshold 194. as determined by comparison function 192« is latched by latch function 200 of controller 70, which prov ides a digital HIGH signal tυ an AKD function 204 of the controller. The occurrence of the Jj A | >!A_ AJSS_^SSSJ Y value exceeding the ninth threshold 198- as determined by comparison function 196, is latched by a latch function 202 of controller 70, which provides a digital HIGH signal to the AND function 204. W hen the AND function 204 is ON or HIGH, as a result of receiving digital HlGI-I signals from both of the latch functions 200 and 202, the AND function 204 provides a digital JHlGH signal to an AND function 206. The AND function 206 receives the output of both the AND function 204 and the AND function 100. Unϋke the control process shown in Fig. 5, the AND function 100 does not provide its output to the latch function .102.

Instead, the AND function 100 provides its output to the AND function 206. When ϊhe AND function 206 is ON or HfGH, as a result of receiving digital HIGH signals from both of the AND functions 204 and 100, the AND function 206 provides a digital HIGH signal to the latch function 102 of the controller 70, which provides a digital HIGH signal to the AND function 104 of the controller.

Thereafter, the control process of Fig. ? proceeds in the same manner and with the same functions as the control process of Fig. 5.

The foregoing subroutine using the signal SSS_1 Y from the satellite sating acceleration sensor 68 can also be employed in the same manner in the control process of Fig. 6.

From the above description of the invention, those skilled in the art wiH perceive improvements, changes and modifications. Such improvements, changes, and/or modifications within the skill of the art are intended to be covered by the appended claims.

Claims

Having described the Invention, the following is claimed:

1. An apparatus for controlling an actiiatable occupant restraint device of a vehicle, said apparatus comprising: a crash acceleration sensor for sensing crash acceleration at a vehicle location and providing a first crash acceleration signal indicative thereof; a side pressure sensor for sensing pressure in a chamber disposed at a side of the vehicle and providing a side pressure signal indicative thereof; and a controller for actuating the actiiatable occupant restraint device in response to the first crash acceleration signal and the side pressure signal, said controller (a) determining a first moving a\erage of acceleration value comprising a moving average of acceleration in a direction generally perpendicular to a longitudinal axis of the vehicle determined from said first crash acceleration signal (b) determining a change in pressure value comprising a change in pressure in said chamber determined from the side pressure signal, and (c) actuating ^aid actiiatable occupant restraint device when both said first moving average of acceleration value exceeds a first threshold and said change in pressure value exceeds a second threshold.

2. The apparatus of claim 1 wherein said change in pressure \alue comprises change so pressure in said chamber divided by ambient pressure,

3. The apparatus of claim 1 wherein said actuatable occupant restraint device is an inflatable restraint device mounted at the side of the vehicle.

4. The apparatus of claim I wherein said chamber is a chamber in a vehicle door.

5. The apparatus, of claim 1 wherein said \ ehkle location is a generally central vehicle location and said apparatus further comprises a side satellite acceleration sensor mounted in side structure of the vehicle for sensing crash acceleration in a direction general!} perpendicular to the longitudinal axis of the \ chicle and providing a second crash acceleration signal indicative thereof, said controller determining a second moving average of acceleration value comprising a men ing average of acceleration in a direction general!} perpendicular to the longitudinal axis of the vehicle based on said second crash acceleration signal and actuating said aciuatable occupant restraint deuce when said first moving average uf acceleration value exceeds a first threshold, said change in pressure \alue exceeds a second threshold, and said second moving average uf acceleration \alue exceeds a third threshold,

6. The apparatus of claim 5 further comprising a satellite safing acceleration sensor mounted on the vehicle for sensing crash acceleration in a direction generally perpendicular to the longitudinal axis uf the vehicle and providing a third crash acceleration signal indicative thereof, said controller determining a third nun ing average of acceleration value comprising a moving of acceleration, in a direction general 1> perpendicular to the longitudinal axis of the vehicle based on said third crash acceleration signal and actuating said actuatable occupant restraint device when said first moving average of acceleration value exceeds a first threshold, said change in pressure \alue exceeds a second threshold, said second moving average of acceleration value exceeds a third threshold, and said third

ing average of acceleration

exceeds a fourth threshold.

7, The apparatus of claim 1 wherein said vehicle location is a location at a side of the vehicle and said apparatus further comprises a central crash accekration sensor at a generally central vehicle location for sensing crash acceleration in a direction general!}' perpendicular to the longitudinal axis of the vehicle and providing a secood crash acceleration signal indicative thereof, said controller determining a second moving average of acceleration vaine comprising a moving average of acceleration in a direction generally perpendicular to the longitudinal axis of the vehicle based on said second crash acceleration signal and actuating said actuatable occupant restraint device when said first moving average of acceleration value exceeds a fust threshold, said change in pressure value exceeds a second threshold, and said second moving average of acceleration value exceeds a third threshold.

8, The apparatus of claim 7 further comprising a satellite sating acceleration sensor mounted on the vehicle for sensing crash acceleration in a direction generally perpendicular to the longitudinal axis of the vehicle and providing a third crash acceleration signal indicative thereof, said controller determining a third moving average of acceleration value comprising a moving average of acceleration in a direction generally perpendicular to the longitudinal axis of the vehicle based em said third crash acceleration signal and actuating said acmatabϊe occupant restraint device when said first moving average of acceleration value exceeds a first threshold, said change in pressure value exceeds a second threshold, said second moving average of acceleration value exceeds a third threshold, and said third moving average of acceleration value exceeds a fourth threshold.

9, A method for controlling actuation of an actuatable occupant restraint device of a vehicle, the method comprising the steps of: sensing crash acceleration at a vehicle location and providing a first acceleration signal indicative thereof; sensing pressure in a chamber disposed at a vehicle side and providing a side pressure signal indicative thereof: determining a ing average of acceleration value comprising a moving average of acceleration in a direction generall^y perpendicular to a longitudinal aλis of the vehicle determined from said first crash acceleration signal; determining a change in pressuie \ alue comprising a change in pressure in said chamber determined from the side pressure signal; and actuating sakl aetuauble occupant restraint device when both said first moving average of acceleration value exceeds a first threshold and said change in pressure value exceeds a second threshold

10. The method of claim 9 wherein the step of determining a change in pressure value comprises determining said change in pressure in said chamber divided by ambient pressure.

i i , The method of claim 9 wherein said actuatable occupant restraint dcv ice is an inflatable restraint mounted at the side of the \ ehicle,

12. The method of claim 9 wherein said chamber is a chamber in a vehicle door.

13. The method of claim 9 wherein sakl vehicle location is a general l> central vehicle location and said method further comprises the steps of sensing crash acceleration in a direction generally perpendicular tu the longitudinal axis of the vehicle at a -vehicle ^ide, pro\ iding a second crash acceleration signal indicative thereof, and determining a second moving average of acceleration value comprising a moving average of acceleration ΪΏ a direction generally perpendicular to the longitudinal axis of the vehicle based on said second crash acceleration signal and wherein said step of actuating the actuatable occupant restraint device comprises actuating said actuatable occupant restraint device when said first moving average of acceleration value exceeds a first threshold, said change in pressure value exceeds a second threshold, and said second moving average of acceleration value exceeds a third threshold.

14. The method of claim 13 further comprising the steps of sensing crash acceleration in a direction generally perpendicular to the longitudinal axis of the vehicle at a satellite safiog location of the vehicle, providing a third crash acceleration signal indicative thereof, and determining a third moving a\crage of acceleration value comprising ά moving average of acceleration in a direction generally perpendicular to the longitudinal avis of the vehicle based on said thhd crash acceleration signal, arid wherein said step of actuating the actuatable occupant restraint device comprises actuating said actuatable occupant restraint device when said first moving average of acceleration value exceeds a first threshold, said change in pressure \a!ue exceeds a second threshold, said second moving average of acceleration value exceeds a third threshold, and said third moving average of acceleration value exceeds a fourth threshold.

15. The method of claim 9 vι herein said vehicle location is a location at a side of the vehicle and said method further comprises the steps of sensing crash acceleration in a direction generally perpendicular tυ said longitudinal axis of the vehicle at a generallv central vehicle location, providing a second crash acceleration signal indicative thereof, and determining a second moving average of acceleration value comprising a moving average of acceleration in a direction general!}' perpendicular to said longitudinal axis of the \ chicle determined from said second crash acceleration signal, and wherein said step υf actuating the actuatabie occupant restraint device comprises actuating said aetuatahie occupant jestraint device when said first moving average of acceleration value exceeds a first threshold, said change in pressure v αluε exceeds a second threshold, and said second moving average of acceleration value exceeds a third threshold.

16. The method of claim 15 further comprising the steps of sensing crash acceleration in a direction generally perpendicular to the longitudinal axis of the vehicle at a satellite safing location of the vehicle, providing a third crash acceleration signal indicative thereof, and determining a third moving average of acceleration value comprising a moving average of acceleration in a direction generally perpendicular to the longitudinal axis of the vehicle hased on said third crash acceleration signal, and wherein said step of actuating the actuatable occupant restraint device comprises actuating said actuatable occupant restraint device when said first moving average of acceleration value exceeds a first threshold, said change in pressure value exceeds a second threshold, said second moving average of acceleration value exceeds a third threshold, and said third moving average of acceleration value exceeds a fourth threshold.